The proposed research will complete the terminal data analysis stage of an extensive investigation of the evolution and maintenance of (1) intense, sometimes lethal aggression, (2) rigid vs. modifiable behavior sequences, and (3) the complexity of the behavioral repertoire in populations of mantis shrimp (Stomatopoda, Crustacea) in controlled ecological conditions, particularly with respect to intraspecific and interspecific competition. The objective of this proposal is to provide new and innovative approaches to animal behavior by applying ideas and theories developed in other fields--game theory; optimization theory; catastrophe theory; and the theory of the niche, competitive exclusion, niche overlap and limiting similarity, and species diversity-and using these theories to develop testable hypotheses about the evolutionary stability of fighting behavior in mantis shrimp.